The Ballistic Compression Decelerator of the Teng patent just mentioned involves a projectile with an integral test specimen to be subjected to rain or dust erosion or other environment under consideration during its "flight" downrange. By capturing the specimen without damage through deceleration techniques, it could be examined to determine the effect of the environment upon it.
After the specimen and projectile has been fired and has passed its test environment, it passes through a recovery tube having a series of pressurized compartments. These compartments are sealed with diaphragms which rupture due to the shock wave preceding the projectile. In this manner the projectile does not pierce and break the diaphragm and thus cause damage to the specimen on the nose of the projectile.
In practice, because of the delicate balance of relating projectile speed, shock wave force, frangibility of the diaphragms, and pressure in the compartments, sometimes the projectile would pierce the diaphragm, or strike a piece of the ruptured diaphragm, causing damage to the specimen and thus ruining the test. Because of the expense of the tests and also because of the need for the test information, a more reliable and consistently satisfactory replacement of the diaphragms is needed.